Factors influencing equine chorionic gonadotrophin production in the mare.
Abstract: An opportunity to monitor equine chorionic gonadotrophin (eCG) production during 61 pregnancies in 25 Thoroughbred mares mated to the same Thoroughbred stallion was utilised in order to further knowledge regarding factors involved in the production of this hormone. Objective: To examine the effects of maternal body condition, exercise and parity on eCG production. Methods: In the first experiment, maiden mares were fed either a moderate (n = 9) or an excessive (n = 10) food intake throughout gestation. In the second experiment, 5 mares were exercised daily during pregnancy and eCG production rates were compared to 5 nonexercised mares. In the third experiment, eCG profiles were compared in 9 mares during 3 successive pregnancies. Equine chorionic gonadotrophin secretion was assessed as area under the curve (AUC), peak serum concentration, timing of the peak and the rate of decline. In addition, a mean eCG profile of 61 pregnancies was created to provide means and ranges for the above parameters. Results: In Experiment 1, eCG production was significantly higher in moderately rather than excessively fed mares in terms of AUC and peak eCG concentrations. In Experiment 2, the mean AUC did not differ between exercised and nonexercised animals but mean eCG concentrations were significantly higher in nonexercised mares between Days 60 and 90 of gestation. In Experiment 3, eCG became undetectable significantly earlier in gestation in the third parity. The mean eCG profile of 61 pregnancies showed a peak of 64.5 ± 3.7 iu/ml at 62.4 ± 1.0 days after ovulation and was undetectable by 134.1 ± 1.7 days. Peak eCG levels reduced by 50% 22.6 ± 1.13 days. Conclusions: Some of the factors examined clearly influenced eCG production rate, the secretion of this hormone and its rate of disappearance from the blood. Conclusions: The results provide insights into some factors that govern the production of the placental gonadotrophin, eCG.
© 2011 EVJ Ltd.
Publication Date: 2011-01-19 PubMed ID: 21496079DOI: 10.1111/j.2042-3306.2010.00309.xGoogle Scholar: Lookup
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Summary
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This research evaluates the impact of a mare’s body condition, exercise habits, and the number of times she’s been pregnant (parity) on the production of a hormone known as equine chorionic gonadotrophin (eCG) during pregnancy. It concludes that these factors do have a significant influence on eCG production.
Experiments Conducted
- The study consisted of three experiments involving thoroughbred mares mated to the same stallion, monitoring 61 pregnancies in total. This setup aimed to eliminate the effect of genetic factors on the production of eCG.
- In the first experiment, the diet of the mares was manipulated; some were fed moderately while others were fed excessively during gestation. The goal of this experiment was to investigate the impact of the maternal body condition on eCG production.
- The second experiment compared eCG production rates between mares who were exercised daily during pregnancy and those who were not. This experiment aimed to evaluate the effects of physical activity on eCG levels.
- The third experiment tracked eCG profiles over three successive pregnancies in the same mares (parity) to examine how eCG production changes over multiple pregnancies.
Key Findings
- Experiment 1: Excessively fed mares produced lower levels of eCG in terms of both total produced (AUC) and peak concentrations compared to moderately fed mares.
- Experiment 2: Physical activity did not significantly affect the total eCG produced (AUC), but mean eCG concentrations did drop between the 60th and 90th days of gestation in mares who were exercised compared to those who were not.
- Experiment 3: The amount of time it took for eCG to become undetectable in the blood was significantly less in the third pregnancy compared to earlier ones, indicating that hormonal production rates might decrease with multiple pregnancies.
- A mean eCG profile was created from all 61 pregnancies, providing averages and ranges for peak levels, rate of decline, and disappearance from the blood.
Conclusions
- The findings confirm that factors like diet, exercise, and parity significantly influence eCG production in mares during pregnancy, thus affecting the conditions of the gestation period.
- This study advances our understanding of how specific factors govern the production of eCG, a hormone vital for maintaining and supporting pregnancy in mares. This insight could be fundamental in improving care for pregnant mares and improving birth outcomes.
Cite This Article
APA
Wilsher S, Allen WR.
(2011).
Factors influencing equine chorionic gonadotrophin production in the mare.
Equine Vet J, 43(4), 430-438.
https://doi.org/10.1111/j.2042-3306.2010.00309.x Publication
Researcher Affiliations
- The Paul Mellon Laboratory of Equine Reproduction, Cheveley Park, Newmarket, UK. sandrawilsher@hotmail.co.uk
MeSH Terms
- Animals
- Body Weight / physiology
- Chorionic Gonadotropin / blood
- Chorionic Gonadotropin / physiology
- Eating / physiology
- Female
- Horses / blood
- Horses / physiology
- Parity / physiology
- Physical Conditioning, Animal / physiology
- Pregnancy
Citations
This article has been cited 7 times.- Lösle M, Lin CW, Beil-Wagner J, Aebi M, Buch T. Comparison of pregnant mare serum gonadotropin products with surprising differences in protein content. Sci Rep 2025 Feb 25;15(1):6824.
- Thompson RE, Meyers MA, Palmer J, Veeramachaneni DNR, Magee C, de Mestre AM, Antczak DF, Hollinshead FK. Production of Mare Chorionic Girdle Organoids That Secrete Equine Chorionic Gonadotropin. Int J Mol Sci 2023 May 31;24(11).
- Manteca Vilanova X, De Briyne N, Beaver B, Turner PV. Horse Welfare During Equine Chorionic Gonadotropin (eCG) Production. Animals (Basel) 2019 Dec 1;9(12).
- Read JE, Cabrera-Sharp V, Kitscha P, Cartwright JE, King PJ, Fowkes RC, de Mestre AM. Glial Cells Missing 1 Regulates Equine Chorionic Gonadotrophin Beta Subunit via Binding to the Proximal Promoter. Front Endocrinol (Lausanne) 2018;9:195.
- Brosnahan MM, Silvela EJ, Crumb J, Miller DC, Erb HN, Antczak DF. Ectopic Trophoblast Allografts in the Horse Resist Destruction by Secondary Immune Responses. Biol Reprod 2016 Dec;95(6):135.
- Cohen L, Bousfield GR, Ben-Menahem D. The recombinant equine LHβ subunit combines divergent intracellular traits of human LHβ and CGβ subunits. Theriogenology 2015 Jun;83(9):1469-76.
- Antczak DF, de Mestre AM, Wilsher S, Allen WR. The equine endometrial cup reaction: a fetomaternal signal of significance. Annu Rev Anim Biosci 2013 Jan;1:419-42.
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